The trunk communication systems are the systems in which a group wireless channels shared by multiple mobile stations and the private mobile communication systems of these channels are used dynamically. They are mainly applied to corporations and enterprises, police, policeman and army and etc which have higher demand for functions of command, dispatching.
The use strategy of present trunk communication systems forward channels is; only one mobile station is active state in one group at one time, the mobile station data sent forward in the group are same, i.e., the mobile stations in the group share forward channels. But for the use of reverse channels, there are two present manners:
First manner, the mobile stations in the group in a cell, comprising mobile stations in active state and mobile stations in idle state, establish each reverse channels for sending signaling information respectively.
Second manner, the mobile stations in idle state in the group in a cell only establish a sharing reverse channel for sending signaling information, all mobile stations in idle state use the sharing reverse channel in the manner of anticipating occupy.
For the large-scale dispatching systems concentrating a mass of mobile stations within a certain region range, the above first manner needs to establish each reverse channels for a mass of mobile stations within the group in a cell. This manner is hard to realize in both air resource and physical resource. That is to say, the limit of resources cause the number of the groups in a cell and the number of the mobile stations in the groups are limited considerably.
In the second manner, the mobile stations in the groups share a reverse channel, when the mobile stations send reverse signaling on this shared channel, the signaling on different mobile stations are prone to collide, causing the mobile stations signaling sending failure and reducing the air capability.